One of the parameters to Execute is a set of environment variables. You could
get all the current variables, change the CWD, and then pass that block in.
This does not mutilate the parent shell's environment variables.
Per which built-in environment variables are R/O - that is clearly defined in
the UEFI Shell Specificaiton. I don't remember off the top of my head.
From: Duane Voth [mailto:dua...@gmail.com]
Sent: Thursday, June 13, 2013 2:10 PM
To: Carsey, Jaben
Cc: edk2-devel@lists.sourceforge.net
Subject: Re: [edk2] Setting an application's current working directory
Importance: High
Indeed there are 4! But have been using ShellPkg for several months now.
So you are suggesting that I set the CWD variable in my current program before
calling ShellExecute()? Clearly I can't use gEfiShellProtocol->SetEnv(EnvKey,
EnvVal, Volatile) because this would set the *shell's* current working
directory? (why does this function exist? Shouldn't it be taboo for a child
program to affect the parent's environment?)
Now there is an Env argument for ShellExecute where a separate copy of the
environment could be built by the popen code from prg2's env for prg3, which
would not mutilate the envronments for prg1 or prg2 - but I can't get it to
work as of yet...
here's a picture:
(prg1) Shell2.efi (shell starts python via a command line)
(prg2) Python.efi (python's os.popen() - which I'm attempting to
implement - builds the Env for prg3 and
replaces the cwd value with a new value
to run a new shell command lets say
'dir')
(prg3) Shell2.efi (second shell executing 'dir > tmpfile')
If python uses gEfiShellProtocol->SetEnv() it will change (prg1)'s cwd, no?
This is the only thing that makes sense - but I'm having to mess with the
StdLib a lot to support the POSIX idea of an individual cwd per program.
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